The major changes I noticed between the two editions are as follows:

Limits prevent characters from being overly min-maxed. Each of them is centered around an attribute that is typically dumped in normal characters; the most important attribute for the physical limit, for instance, is Strength, though other attributes weigh in they have the same impact as Strength does alone. This means that you can't build a "never gonna fight close quarters" build and just dump strength and expect to do well in other physical areas, encouraging a well-rounded thing.

Mystic adepts get a huge buff. I'm not exactly sure that this is a bad thing; they still can't astrally project, but they get the powers of both mages (other than astral) and phys-ads pretty nicely. Were they still using the BP system, this would be a flaw, and I'm not sure about allowing them as the third pick on your priority system, but I think the reason that people are upset is because they don't astrally project as much as they should when not a mystic adept.

The priority system really makes things a lot better. It prevents some of the worst cheesing during character creation (don't get me wrong-it's still possible, but you have to know what you're doing and make some sacrifices).

Combat's been changed rather heavily on the bookkeeping, but not so much the execution. The Accuracy limit keeps pistols from killing Great Dragons, which is a nice touch, but also discourages just dumping into the newly increased skills and maxing them out right away. It also makes smartlinks a more tangible advantage, as do laser sights. Armor is now a single rating for stun and physical, which makes it a lot easier for new players to understand, and, in my opinion, more realistic.

Hacking's a lot better. Mind you; the wireless thing contains some logic holes and gimmicks with the new benefits it gives stuff like cyberware or laser sights, but hackers can enjoy a target rich playground with new rules for hacking that make prepping a hacker 90% easier and playing one about 50% easier; GM'ing hacking also became a lot easier. In addition, some of the more broken technomancer stuff has been revised so you now have a reason to play a decker instead of a technomancer every single time.

All in all, it's faster and more streamlined. If you want my "reviewer" version, you can check it out on my blog, but I've said pretty much everything I said there here, only without the sales pitches.

Definitions

We all have our limits and boundaries. Lines and veils are different ways to handle those boundaries in play.

• A line is, well, a line — a hard limit, something we do not want to cross. Lines represent places we don't want to go in roleplaying.

  "There is no torture in the events in our game. We don't do it, NPCs don't do it to us or to each other. Whether it happens elsewhere in the setting is not an issue in terms of enjoying play."¹

• A veil is a "pan away" or "fade to black" moment. When we veil something, we're making it a part of the story, but keeping it out of the spotlight. Think of it as a way to still deal with certain themes while avoiding having to describe them in graphic detail.

  "Torture does happen in the game world and may happen in our game in some way or another. But if and when it does, we do not role-play it directly or depict it verbally. Everyone is trusted to play their characters as reacting to it appropriately without us having to experience it vicariously."¹

Background

This terminology came out of Forge discussion some years ago, plus Sex and Sorcery, a supplement to the game Sorcerer. It's a feature of indie-RPG discussion because the community strives to be inclusive but also features a lot of games that deal with difficult content.

Techniques in Play

You can establish some limits ahead of time, as you can see in the examples above. This is a good approach for stuff you know will come up, because it's central to the game system, the setting, or the genre you have in mind. Oftentimes groups do this using shorthand like "Let's keep it PG-13."

Where an understanding of lines and veils really shines, though, is in helping you to communicate about issues as they arise during play. This is something every gamer should learn since it's part of looking out for each other's fun, and there's no way to perfectly plan your way around every issue before the game starts.

The most important thing is to make it easy to speak up. That means you should cultivate a non-judgmental atmosphere. A basic lines-and-veils discussion kinda looks like this:

"Ouch!"

"Oops. Sorry. Let's fix that."

Don't try to argue someone to give in on their limits. Don't try to assign blame to anyone. The person who's feeling uncomfortable may want to talk about it, or they might not; either way is okay. Identify the problem, fix the problem in a way that addresses their specific needs and desires, make a mental note of it for next time, and continue play.

In many cases, a group can do fine without formal structure for this. However, for tricky subjects or gaming with strangers, formal systems are a big help. Variations include:

• X-Card is a physical token representing "This is crossing a line for me." (Interestingly, there's a modification that combines that with "This is difficult but I enthusiastically want you to keep going.")
• Script Change generalizes this to a kind of "movie-editing" mindset, including tricks like slow-stepping through specific content.
• The Luxton Technique (archive.org mirror) focuses on giving the affected player room to resolve situations in way that best brings them a sense of comfort or closure. I recommend reading the linked article even if you already know you're going to be playing in a space with X-Card, because it highlights how the process itself isn't one-size-fits-all.
• The TTRPG Safety Toolkit is a curated collection of various tools and techniques of this kind.

Really, lines and veils in play are about communication, attitude, and interpersonal skills:

The Veil or The X-Card doesn't replace our complicated interpersonal toolsets that we've spent our whole lives developing... it signals that now is the time to use them. Maybe the stock solution of "edit out the problem content, keep moving" works, but maybe not. It's case + person + issue + game-dependent.²

However you communicate about limits and comfort, remember that signaling devices aren't a perfect substitute for social awareness. Just because someone isn't explicitly telling you they have a problem doesn't mean everything is fine always. A shy player or someone who's been surprised by a trauma trigger might not be able to assert a line in the moment. So keep an eye on people's actual reactions and adjust your play accordingly.

1 - Examples from Sorcerer author Ron Edwards.

2 - Commentary from Monsterhearts author Avery Alder. Check out the free mini-supplement Safe Hearts (PDF link) for more advice about dealing with emotionally challenging content.